<!DOCTYPE html>
<html lang="en">

<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>加减计数器</title>
</head>

<body>
    <!-- 显示计数器数值的区域 -->
    <span id="counter">0</span>
    <!-- 减按钮 -->
    <button id="decrease">-</button>
    <!-- 加按钮 -->
    <button id="increase">+</button>

    <script src="script.js"></script>
</body>

</html>